What happens to bumblebees in autumn?

Late summer is the time when most bumblebees begin to behave in usual ways that may seem alarming, but we’re here to shed some light on them. Instead of simply feeding upon flowers, they can now be seen mating, digging holes to hibernate in and slowly feeding upon flowers and dying en masse. What is the explanation for all of this? Read on to find out.

Firstly, we have had a few photos sent in from people who are alarmed to find that the queen bees are being ‘attacked’ by smaller bees which cling to their backs. Fortunately, it’s just what bumblebees look like when they’re mating, as you’ll see in the photo below (the queen is the large one, the male is smaller)

So when the queen has mated she will go into hibernation. She will burrow into soil and hibernate through the winter, using fat reserves to keep herself alive. Queens can survive temperatures down to minus 19 Celsius by producing a kind of ‘antifreeze’ in their bodies. Bumblebees are surprisingly good at digging, as you can see in the photo here.

But what happens to the rest? Unfortunately, it’s the end of the road for the them: the old queen, all her workers, and all the males die at the end of summer. You have probably seen some bees clinging lifelessly to flowers, only raising a sorry leg in defence when you get close to them. You might even have found dozens of dead bees in your garden, especially below the plants which they like to feed upon most – buddleia is the most commonly reported plant.

It’s all part of the bumblebee lifecycle though. The best thing we can do to help bumblebees now is to have the right plants for the final few queens to feed upon, and be vigilant when we are turning compost or digging soil - there might be a queen bumblebee whose hibernation could be disturbed like the one in this photo.